Periodic Flow Detection for Single-Clock Packet Delay Estimation
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Solution Overview
Problem
Existing methods for estimating packet delay in networks require synchronized clocks at multiple measurement points, making them impractical for applications other than VOIP where the transmission time interval is unknown.
Innovation Solution
A periodic flow detection device and method that classifies packets into flows based on included information, evaluates their periodicity, and detects periodic flows to estimate packet delay using a single clock.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If passive measurement method is used to measure one-side delay in network, then delay measurement can be performed, but synchronized clocks at multiple measurement points are required
Solution Approach 1:
The invention extracts and utilizes only the reception time information from packets, eliminating the need for transmission time information or synchronized clocks at multiple points. By focusing on what can be obtained at a single measurement point (reception time), the complex requirement for clock synchronization is removed while maintaining delay measurement capability.
Solution Approach 2:
The measurement system uses only its own clock at the reception point to measure delay, without requiring external synchronized clocks. The packet's embedded reception time stamp serves the measurement purpose directly, making the system self-sufficient and eliminating external synchronization dependencies.
2Device complexity
If delay estimation method using single clock is used, then clock synchronization requirement is eliminated, but transmission time interval must be known
Solution Approach 1:
Instead of requiring complete knowledge of transmission parameters (time interval, pattern), the invention uses only the received packets themselves and their reception times. By analyzing the actual received packet sequence and timing, the system derives delay information without needing excessive information about the transmission side configuration.
Solution Approach 2:
Rather than trying to reconstruct transmission parameters to calculate delay, the invention inverts the approach by directly measuring delay from reception time patterns. Instead of using transmission time interval as input to calculate delay, the reception time sequence itself becomes the basis for delay estimation.
3Measurement precision
If related art delay estimation method is applied to non-VOIP applications, then delay estimation may be achieved, but it requires known transmission time interval which is often unavailable
Solution Approach 1:
The invention creates a universal delay measurement method that works across different application types (VOIP, streaming, file transfer, etc.) without requiring application-specific knowledge. By using only packet reception time information that is universally available in IP networks, the method achieves broad adaptability while maintaining measurement capability.
Solution Approach 2:
The invention changes the measurement parameter from transmission-time-based (requiring known interval) to reception-time-based (using actual received timestamps). This parameter change makes the method adaptable to various applications since reception time information is universally available regardless of application type or transmission pattern.
Data Source
AI summary
A periodic flow detection device include a packet classification unit configured to classify packets into a plurality of flows on the basis of information included in acquired packets; a flow evaluation unit configured to evaluate a possibility that each of the plurality of flows is periodically transmitted on the basis of time at which the packets are acquired; and a flow detection unit configured to detect, from the plurality of flows, a periodic flow that is a flow to which packets periodically acquired belongs on the basis of a result of the evaluation.